In flotation assay, uniformly-sized liposomes are required because liposomes should have
same buoyancy. Moreover, liposomes must have enough radiuses (about 100nm in radius) to float in sucrose buffer.
Using Extruder device(Avanti), we prepared liposome of 120nm in radius.

Result of agarose gel electrophoresis of the sample of flotation assay
The result of 1% agarose gel electrophoresis(100V,30min). In this measurement, the fluorescence of Cy5, which is
integrated into DNA origami(Rect tile[1]) ,is observed. Fraction1 is the liquid in the top layer, and fraction 5 is in the bottom layer. Fraction 6 is the sample retrieved from precipitation. DNA origami solely was also loaded on the extreme right lane.

Fluorescence intensity of the samples of flotation assay(DNA Rect tile +liposome)
Although the size of liposome might change during the flotation assay(data not shown), the intensity of the fluorescence of NIL(Nile Red, ex 500nm, em 550~700nm )
suggests the amount of lipid membrane,liposome. The fluorescence spectrum of water was subtracted as background

[Discussion]

To confirm the flotation assay, mixed tiles(DNA origami) and liposomes were assayed. Five samples (fraction 1,2,...,5, from the top) were
retrieved from supermetant liquid and a sample(fraction 6) from precipitation by the addition of buffer used in
assay. When the sample, tile mixed with liposomes, were assayed, tiles were observed in the top layer. The distribution of liposomes is observed by the fluorescence of NIL(Nile Red).

We examined how DNA-tube was synthesized efficiently by using the method which is introduced in “Rapid Folding of
DNA into Nanoscale Shapes at Constant Temperature” (Jean-Philippe J. Sobczak et al, Science, 2012, 338, 1458)
[2]. In
the figure above, two bands derived from scaffold or DNA-tube were showed with cursors. At 56.4℃, the scaffold
band was diminished. In contrast, the DNA-tube band was concentrated. In fact, the ratio of DNA- tube band
to scaffold band was the greatest at this temperature, which means we succeeded in synthesizing DNA-
tube efficiently and improving the yield of DNA-tube.